title: Bilateral passive leg raising attenuates and delays tourniquet deflation-induced hypotension and tachycardia under spinal anaesthesia: a randomised controlled trial.
abstract: BACKGROUND
  The pneumatic tourniquet is frequently used in total knee arthroplasty. Tourniquet deflation may result in hypotension and tachycardia caused by the rapid shift of blood volume back to the ischaemic limb and a decrease in cardiac preload. Passive leg raising (PLR) represents a 'self-volume challenge' that can result in an increase in preload. Such a PLR-induced increase in preload was hypothesised to attenuate the decrease in preload resulting from tourniquet deflation.
  
  
  OBJECTIVE
  To evaluate the effect of PLR on hypotension and tachycardia following tourniquet deflation.
  
  
  METHODS
  A randomised controlled trial.
  
  
  METHODS
  Single medical centre.
  
  
  METHODS
  Seventy patients who underwent unilateral total knee arthroplasty were randomised into two groups: tourniquet deflation with PLR (n = 35) or without PLR (control group, n = 35).
  
  
  METHODS
  Patients in both groups were administered a single dose of plain bupivacaine for spinal anaesthesia. The pneumatic tourniquet was inflated on the thigh and the surgery was performed. The study composed of four steps: for the PLR group, step 1 - inflation of the tourniquet while the patient was supine; step 2 - the patient's legs were raised to a 45° angle; step 3 - the tourniquet was deflated while the patient's legs were still raised; and step 4 - the legs were returned to the supine position. In the control group, the same perioperative procedure was used, but PLR was not conducted.
  
  
  METHODS
  The patients' blood pressure and heart rate were measured before, during and after tourniquet deflation.
  
  
  RESULTS
  After tourniquet deflation, the magnitude of the changes in blood pressure and heart rate was less in the PLR group than that in the control group. In addition, the blood pressure nadir also occurred later in the PLR group than in the controls.
  
  
  CONCLUSIONS
  Bilateral PLR is a simple, reversible manoeuvre that mimics rapid fluid loading. Bilateral PLR attenuates the severity of, and delays the time to, hypotension and tachycardia following deflation of a lower limb tourniquet.
  
  
  BACKGROUND
  ClinicalTrials.gov number NCT01592669.
authors.affiliation: From the Department of Anaesthesiology (G-SH, C-HC, W-HC); Department of Orthopedics, Tri-Service General Hospital, National Defense Medical Center, Taipei (C-CW, L-CL); Division of General Pediatrics, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan (M-HH); School of Public Health (M-SL); Division of Cardiovascular Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan (C-ST); Department of Anesthesiology, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan (X-XH).
authors.forename: Go-Shine
authors.initials: GS
authors.lastname: Huang
authors.forename: Chih-Chien
authors.initials: CC
authors.lastname: Wang
authors.forename: Mei-Hua
authors.initials: MH
authors.lastname: Hu
authors.forename: Chen-Hwan
authors.initials: CH
authors.lastname: Cherng
authors.forename: Meei-Shyuan
authors.initials: MS
authors.lastname: Lee
authors.forename: Chien-Sung
authors.initials: CS
authors.lastname: Tsai
authors.forename: Wei-Hung
authors.initials: WH
authors.lastname: Chan
authors.forename: Xhang-Xian
authors.initials: XX
authors.lastname: Hsieh
authors.forename: Leou-Chyr
authors.initials: LC
authors.lastname: Lin
mesh_terms: D000368:Aged; D000775:Anesthesia, Spinal; D019645:Arthroplasty, Replacement, Knee; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D007022:Hypotension / Q000517:prevention & control*; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000517:prevention & control*; D014111:Tourniquets / Q000009:adverse effects*